Oops, it doesn't look like 'pain in the ass day' is a national day..

Other days

promposal

Promposal Day
hiv awareness

Hiv Awareness Day
slime

Slime Day
tell a fairytale

Tell A Fairytale Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
me

Me Day
ask out your crush

Ask Out Your Crush Day
tulip

Tulip Day
cursing

Cursing Day
ruby

Ruby Day